Pain In The Lower Back.Is X-ray Needed?

I am a gymnast, and I hit my back really hard on the vault like 3 and a half weeks ago. For two weeks the pain just got worse each day, and now it has just leveled off. It hurts to arch my back, stand up straight or do any gymnastics at all. Its kind of a sharp pain right on my spine/lower back. I went to urgent care a week ago, she took two basic x rays. Then said it wasn't broken and gave me some muscle relaxers that have not helped at all. The athletic trainer suggested I see a back specialist, but I'm not sure if I should.